Rapid operation air lock for closed vessels



Jan. 19, 1954 AVERY RARID OPERATION AIR LOCK FOR CLOSED VESSELS Filed Sept. 5, 1952 FIG.I

FIG. 2

INVENTOR.

ROBERT 7: AVERY BY a ,4 7' TOR/VE Y Patented Jan. 19, 1954 UNITE-D STATES PATENT OFFICE RAPID OPERATION AIR LOCK'FOR ones- D vEssELs Robert Avery; Oakland, Galif., assig-nor to United States of America as represented by the 'United States Atomic Energy Commission Application sefitcmb'er 5, 1952, Serial No. 307,9'77 .7 Claims. (01.214-17) v I invention relates to the apparatus :of the type known as air looks, such structures providing access cham'bers adjacent iclosed vessels. More particularly, .';the invention is concerned "withtair lock means doruse with the vacuum vessels .of'ma'ss spectrometers or the like. In the @operation of the latter, it is frequently desired to transfer .anobject -from the "exterior to the interior .of 'the'wacuum chamber 'wfithout "contami-nating the vacuum with air. A typical-procedure is :the introduction of a Small sample of a radiation-emitting substance into a mass spec- -trometer vacuum chamber'to :enable a study to be made of :the character'istics of 'the'iradiation. A principal factor in the foregoing operation is the time "element. That is, when employing a substance Whose "radiationeemitting ability rapidly 'Fdiminishes over ashor-t interval of time, it is essential that the time required to introduce the substance into the chamber be as short as Possible. 7 V

Prior to the present-invention, so far as 1 am aware, devices for'facilitating the foregoing operation have generally uti'lized a plurality of compression tap valvesand manually operated seals. The time consuming 'manipulation'ofsuch controls despite optimum conditions was "a serious' disadvantage. To "overcome the numerous shortcomings of the arrangementsreferred to and to reduce the time-element mentioned were the 'desiderata' resulting in the present inventi'on. Broadly'stated, the latter provides-a chamber or air lock sealingly'secured to the *apertured wall of a vacuum chamber of the type referred to and including -a*-spr'ing-pressed "closure which is movable into sealing contact with the wall portion defining said aperture and having also a position of 'translation away from and to one side of :said aperture whereby the usef a probe for carrying the radiation-emitting substance axially of the aperture into the interior of the evacuatedvesselisfacilitated. I

It is morje especially an object ofthe invention to'prov ide air lock apparatus providing a completely unobstructed opening into the vacuum chamber. i

Another object of the invention is to provide in an .air lock apparatus an aperture closure plate having uniform peripheral sealing pressure i I v 7 Another object is to provide lock apparatus in which the ilexiblesealing elements, :such'as gaskets ior thenecessary movable parts of the air lock, are of such configuration as to pre- I2 vent excessive wear -or unusual deformationduring-long use thereof.

Yet another object oftheinventi'on istol'provide air lock apparatus which is readilydetachablefromthe vacuum chamber. I

"An additional 'object of the invention is to provide in air lock apparatus, an integral wall structure incorporating *a probe guide which not only insures -accurate*a1ignment of the latter through all positions thereof, but materialli speeds up the manual insertion==and withdrawal of the latter.

A still further object of the invention' is to provide "an air lock "apparatus Cha'raGteriZed' by rugged =constructionand quick operation and one that involves both a minimum "of first cost and insignificant service expense and servicing time.

For abetter understanding of the preferred form of the airlock of this invention, reference is now made to the accompanying drawing wherein: r Y

Figure lis a 'cross section view of the invention showing also associated apparatus;

xF-igurezz' is 'a cross section view taken on the line 2-;2-of Figure 1, and

Figure 3 is a perspective view of a vacuum chamber "equipped with the improved air lock.

Referring to thedrawing there is shown at?) the wall or a vacuum vessel which may be that or -'a mass spectrometer, for example, having-an :ap'ertureifi which may be closed by a" closure plate 1' disposable theme-cross and also movable laterallyth'ereof by means-later to be described herein. Surrounding closure plate I and mounted fionithe'wallfi by 'means'such asbolts i8 extending through ears Bis an air lock housing struc'-- ture H of generally box-like configuration having an open's'idecbplanar with the outer surface of 'wall 5 as are ears 9 which are integral with said housing. I I

Housing H which is preferably made as an integral casting "includes an outwardly extending tubular portion I? of substantiallength having an inner cylindrical bore H in alignment with aperture '6 of the vacuum vessel. An end wall 14 of housing 'I I remote from bore 13 and extending a generally normal direction to the open side of the housing is provided with a threaded opening receivingan axially elongated sleeve [5 serving as a bearing for a closely fitting shaft 15 therein. The latter is sealed against the admission of all into the housing ll by means of a plurality of chevron typeseals ll, well known in "the art, which seals are retained by a suitable gland nut l8 threaded interiorly and adjacently into the annular recess wherein seals l1 are seated. Gland nut [8 by virtue of its axial elongation provides a substantial bearing for shaft l6 supplementing the similar action of sleeve l5.

Reference is now made particularly to Fig. 2 for an understanding of the actuating mechanism interconnecting shaft 16 and closure plate I, which is effective to seal aperture 6, as well as to move such closure plate away from said aperture and thereafter translate the same to a position entirely to one side thereof of aperture 6. It will be seen that in the closed position of the air lock an eccentrically disposed end portion l9 of shaft it engages an end wall 20 of housing II opposite wall M Serving as a terminal stop for shaft I6 when the latter is in such position. A

generally rectangular follower block 2! having a generally elliptical slot 22 extending between the opposite faces thereof along an axis parallel to the axis of shaft it serves as a closed cam surface. Slot 22 surrounds portion I 9 of shaft l6 being retained thereon by the terminal shoulder of shaft l6 adjacent thereto and by means such as an annular flange 23, which may be suitably secured to shaft [5 adjacent follower block 2!. The latter is united to closure plate 1 by means such as a pair of bolts 24 passing through such block and threaded into closure plate I, one bolt being on each side of slot 22 and aperture 6, as shown in Fig. 2. By enlarging for a substantial distance the bores in follower block 2| through which bolts 24 extend, receses facing closure plate I are provided wherein compression springs 25 surrounding said bolts may be disposed to exert separative pressure between the follower block and closure plate. This spring action may be varied through the adjustment of lock nuts 26 threaded onto the portions of bolts 24'which extend outwardly from the follower block, as will be readily apparent. Through the provision of a peripheral gasket 2! disposed in a suitable recess in the surface of closure'plate 1' facing the wall 5 of the vacuum vessel, it will be seen that an extremely effective seal of equalized peripheral pressure over the opening 6 is attained.

From the immediately preceding description it will be apparent that rotation of shaft l6 in either direction from its position in Fig. 2 corresponding to complete closure of opening 6 will result in movement of follower block 2| and also closure plate I away from said opening; thereafter shaft is may be pulled to the right until it reaches its extreme position in which the end of the closure plate is stopped against end wall l4 providing complete unobstruction of aperture 6. Such rotation and translation of shaft is is conveniently provided by means outside the air lock housing such as a lever 28 secured to the outer end of shaft l6.

An important provision of the invention resides in the substantial axial extent of tubular portion [2 defining correspondingly elongated bore l3. As shown in Fig. 1, an elongated cylindrical probe 32 of diameter corresponding to the diameter of bore [3 and sealed effectively by an appropriate sealing ring 29 seated in an annular recess in such bore, insures continuous alignment of the probe with aperture 6 as the former is projected into a positionwithin the evacuated vessel. The definite terminal positioning of the probe inwardly of the wall 5 is assured'through the provision on the probe of a shoulder 30 of increased diameter, a semi-circular cutout 3! corresponding to the smaller or bore diameter of the probe and fitting thereagainst when the bifurcated strip or ball 33 pivotally connected to each side of the tubular portion [2 and providing such cut-out is suitably adjusted. An elongated slot 34 in each leg of the bail forming the continuation of the pivoting apertures thereof permit the bail to be swung upwardly out of the way when it is desired to fully insert the probe. It will be seen that the bail in its indexing position, shown in Fig. l, definitely indicates the withdrawn position of the probe immediately outside the air lock.

Another opening 35 into the housing II and preferably in end wall 20 thereof is provided for the connection of a remotely disposed vacuum pump (not shown) through conduit 36 and in termediate shut-off valve 3'! connected to housing I I by elbow 33. Inasmuch as in practice it is customary to employ a vacuum pump connected to the conduit 36 which is of lower effectiveness than the pumps connected to evacuate the main vacuum vessel and its continued operation while the aperture 6 is open would result in the backing up of air through the air lock pump and into the main vacuum tank with impairment of the vacuum therein, it is preferred to provide on the shaft 16 a contact actuator 39 which moves in such a position on rotary movement of lever, 28 as to open a suitable switch All and thereby discontinue operation of the pump connected to the air lock.

The operation of the improved air lock is be lieved to be apparent from the foregoing description, as well as the manifold advantages of operation accruing from the unique arrangement of component parts. Upon partial rotation of lever 28 through a predetermined angle which ay conveniently be that which accomplishes opening of switch 40, the latter thereby serving as a stop, the lever 28 is thereafter pulled to the right as far as it will go. With the air lock vacuum pump disconnected the probe having the radioactive expedition.

Although the present invention has been disclosed with respect to a preferred embodiment it will be appreciated by those skilled in the art that numerous modifications and variations are possible within the spirit and scope of theinvention and it is therefore not desired to limit the invention to the exact details described as may be defined in the following claims.

What is claimed is:

1. Air lock apparatus adapted to be sealingly disposed across an aperture in theplanar wall of a vacuum vessel for providing access to the interior thereof under a plurality of vacuum conditions, said apparatus comprising a generally rectangular open-sided housing, an elongated, tubular portion in said housing opposite said open side and in alignment with said wall aperture when said housing is in place, a closure plate for said wall aperture, and manually operable means extending through another wall of said housing" and connected to said closure plate for moving the latter normally to said'p-lanar Wall and intoclosed position across said wall aperture and for moving said closure plate normally away from said wall aperture and thereafter laterally thereof to provide complete unobstruction of the latter.

2..The combination of elements defined in claim 1 and wherein said means comprises an elongated bearing secured in said housing on one side of said closure, an elongated, eccentric shaft having a major portion thereof journaled in said bearing and a resilient seal disposed in said bearing and surrounding said shaft.

3. The combination of elements defined in claim 1 and including a vacuum pump connected to said housing for evacuating the same and an electric switch for said pump disposed adjacent said means and operable by the latter for automatically stopping said pump whenever said closure plate is opened by said means.

4. Air lock apparatus adapted to be sealingly disposed across an aperture in the planar wall of a vacuum vessel for providing access to the interior thereof under a plurality of vacuum conditions, said apparatus comprising a generally rectangular open-sided housing, an elongated, tubular portion in said housing opposite -.%said open side and in alignment with said wall aperture when said housing is in place, a closure plate for said wall aperture, and a rigid shaft extending through another wall of said housing and resiliently and eccentrically connected to said closure plate for moving the latter normally to said planar wall and into positively closed-position across said wall aperture and for moving said closure plate axially away from said wall aperture and thereafter laterally thereof to provide complete unobstruction of the latter.

5. Air lock apparatus adapted to be sealingly disposed across a wall aperture of a vacuum vessel for providing access to the interior thereof under a plurality of vacuum conditions, 'said apparatus comprising a generally rectangular open-sided housing, an aperture in said housing opposite said open side and in alignment with said wall aperture when said housing is in place, an elongated probe disposed in said tubular portion, a vertically slotted closure plate forsaid 6 wall aperture, and means including a rigid shaft extending through another wall of said housing and having an eccentric terminal portion of reduced diameter extending through the vertical slot of said closure plate for moving the latter rectilinearly into closed position across said wall aperture and for moving said closure plate rectilinearly away from said wall aperture and thereafter laterally thereof to provide complete unobstruction of the latter.

6. Air lock apparatus adapted to be sealingly disposed across a wall aperture of a vacuum vessel for providing access to the interior thereof under a plurality of vacuum conditions, said apparatus comprising a generally rectangular, opensided housing, an aperture in said housing opposite said open side and in alignment with said wall aperturewhen said housing is in place, a closure plate for said wall aperture, an elongated bearing extending outwardly from another wall of said housing and having a cylindrical bore therein, an annular chevron type seal disposed in said bearing and surrounding said bore, a

cylindrically bored gland nut threaded into said bearing and into compressive relation with said sealand means including a shaft extending from outside said housing through said nut, seal and bearing and having an eccentric and resiliently biased slot-type connection to said closure plate for moving the latter rectilinearly into positively closed position across said wall aperture and for moving said closure plate rectilinearly away from said wall aperture and thereafter laterally thereof to provide complete unobstruction of the latter.

7. The combination of elements recited in claim 6 and wherein the dimensions of said bearing, seal and nut axially of said shaft exceed the portion of the latter disposed within said housing in the closed position of said closure plate.

ROBERT T. AVERY.

References Cited in the file of this patent UNITED STATES PATENTS Number 

